1. Field of the Invention
The invention relates to a web-fed rotary offset printing machine having transfer cylinders mounted in sidewalls and web-guiding elements for guiding the web at the web inlet or the web outlet while the machine is running so that the transfer cylinders can be moved apart and a printing plate or a printing sleeve can be changed.
2. Description of the Related Art
DE-G 93 11 113 discloses a device in which the printing-material web is guided over two guide rolls, which are designed as cylindrical rollers. The guide rolls are mounted directly in the side walls of the printing units, so that there is no possibility of adjusting the guide rolls. The web stabilization and guidance is carried out by offsetting the web, the protective elements, in the form of continuous rolls, being effective over the entire web width. Setting these elements against or away from the printing-material web is not possible.
U.S. Pat. No. 5,901,648 discloses the practice of guiding a printing-material web by means of a two-part web-guiding element, which is also adjustable, when the transfer cylinders are moved apart. The protective elements extend over the entire web width. The protective elements are designed like fingers and, in their shape, correspond to the curvature of the surface of the two transfer cylinders arranged on either side of the printing-material web. It goes without saying that protective elements configured in this way are expensive.